Question 1

Which of the following is correct?

Accepted Answer

A)  During oxygenic photosynthesis,water is used as a source of electrons;during non-oxygenic photosynthesis,hydrogen sulfide is used as a source of electrons.
B)  During oxygenic photosynthesis,hydrogen sulfide is used as a source of electrons;during non-oxygenic photosynthesis,water is used as a source of electrons.
C)  During oxygenic photosynthesis,oxygen is used as a source of electrons;during non-oxygenic photosynthesis,water is used as a source of electrons.
D)  During oxygenic photosynthesis,oxygen is used as a source of electrons;during non-oxygenic photosynthesis,hydrogen sulfide is used as a source of electrons. A

Question 2

A bacterium was grown in two test tubes filled with media rich in glucose.One tube was sealed to produce anaerobic conditions,and the other was not.A third uninoculated,unsealed tube was used as a control.Glucose utilization by this bacterium causes acid production,which is indicated by a lightening of the media color.If the bacterium is able to produce ATP only by respiration,which result do you expect to receive?

Accepted Answer

A)  lightening of media in the sealed tube only
B)  lightening of media in the unsealed tube only
C)  lightening of media in the sealed and unsealed tubes only
D)  lightening of media in the control tube only
E)  lightening of media in all three tubes B

Question 3

What do Bacteria have in common with Archaea but not with Eukarya?

Accepted Answer

A)  unicellular structure
B)  peptidoglycan cell walls
C)  transcription mechanism begins with formylmethionine
D)  absence of nucleus
E)  all of the above D

Question 4

Use of synthetic fertilizers often leads to the contamination of groundwater with nitrates.Nitrate pollution is also a suspected cause of anoxic "dead zones" in the ocean.Which of the following might help reduce nitrate pollution?

Accepted Answer

A)  growing improved crop plants that have nitrogen-fixing enzymes
B)  adding nitrifying bacteria to the soil
C)  adding denitrifying bacteria to the soil
D)  using ammonia instead of nitrate as a fertilizer
E)  all of the above

Question 5

Imagine that you are given some chemoorganotrophic bacteria to grow.What should you use as a source of energy for this type of bacteria?

Accepted Answer

A)  light
B)  methane
C)  ammonia
D)  sugar
E)  any of the above

Question 6

Multicellularity and large body size of eukaryotic organisms requires high metabolic rates and efficient ATP production by aerobic respiration.How did bacteria change Earth's atmosphere to enable aerobic respiration?

Accepted Answer

A)  Oxygenic photosynthesis by cyanobacteria significantly increased the amount of oxygen in the atmosphere.
B)  Splitting of water during anaerobic respiration by cyanobacteria dramatically increased the amount of oxygen in the atmosphere.
C)  Nitrogen fixation by cyanobacteria decreased the amount of nitrogen in the atmosphere,leading to simultaneous increase of oxygen.
D)  Anaerobic respiration by cyanobacteria increased the amount of oxygen in the atmosphere by reducing the amount of iron oxides that are able to react instantly with oxygen.

Question 7

The purple non-sulfur bacterium Rhodospirillum grows best as a photoheterotroph.What are the most favorable sources of energy and carbon for this bacterium?

Accepted Answer

A)  methane and CO₂
B)  fructose and light
C)  light and CO₂
D)  glucose

Question 8

Figure 28.1 
-Bacteria able to perform the NH₄⁺ + NO₂⁻ → N₂ + 2H₂O reaction have been discovered in laboratory bioreactors and wastewater treatment systems.Researchers predicted that these bacteria should exist in oceans.They measured the concentration of NH₄⁺,NO₂⁻,NO₃⁻,and O₂ in the Black Sea as a function of water depth (M.Kuypers et al.2003 Anaerobic ammonium oxidation by anammox bacteria in the Black Sea.Nature 422:608-11)to determine where in the sea the bacteria might live.Analyzing data presented in Figure 28.1 above,at what depth would you expect to find the bacteria? (Note: In the figure,different scales are used to show concentrations of NH₄⁺,NO₂⁻,NO₃⁻,and O₂.)

Accepted Answer

A)  in the top 5 meters
B)  in the top 50 meters
C)  at a depth of 75 meters
D)  at a depth of 92 meters
E)  below 100 meters

Question 9

What is the major goal of cellular respiration?

Accepted Answer

A)  reduce an electron acceptor molecule
B)  supply cell with fixed carbon
C)  produce ATP
D)  generate O₂
E)  All of the above answers apply.

Question 10

Which are evolutionarily more closely related?

Accepted Answer

A)  bacteria and archaea
B)  archaea and eukarya
C)  bacteria and eukarya
D)  Bacteria,eukarya,and archaea are equally related to each other.

Question 11

You might be interested to know how many different types of bacteria live on the shower curtain in your bathroom.What is the most efficient method for answering this question?

Accepted Answer

A)  enrichment culture
B)  direct sequencing
C)  Enrichment culture and direct sequencing are equally efficient methods.

Question 12

What is the right progression of steps for a direct-sequencing experiment?

Accepted Answer

A)  Lyse cells,purify DNA,amplify genes by PCR,and insert genes into plasmids.
B)  Lyse cells,insert genes into plasmid,purify DNA,and amplify genes by PCR.
C)  Lyse cells,insert genes into plasmid,amplify genes by PCR,and purify DNA.
D)  Purify DNA,amplify genes by PCR,lyse cells,and insert genes into plasmid.

Question 13

Bacteria and Archaea are most easily distinguished from each other by their

Accepted Answer

A)  chromosome structure.
B)  habitat.
C)  transcription and translation mechanism.
D)  reproduction method.

Question 14

To establish a link between a specific bacterium and a skin disease,researchers have shown that bacterium was present in sick persons but not in healthy individuals.They isolated the bacterium in a pure culture and demonstrated that experimental healthy animals injected with this culture became sick.What other experiment do researchers need to perform to be absolutely sure that the bacterium is responsible for the disease?

Accepted Answer

A)  Demonstrate that the bacterium belongs to the pathogenic lineage.
B)  Demonstrate that the bacterium is not able to live outside of humans or animals.
C)  Isolate bacterium from an infected sick animal and demonstrate that it is the same bacterium as the one used for infection.
D)  Demonstrate all of the above.
E)  No experiments need to be done,because there are enough data to establish that skin disease is caused by the investigated bacterium.

Question 15

When some bacteria use lactose as a source of energy,they produce propionic acid and CO₂.What is the name for this process?

Accepted Answer

A)  fermentation
B)  cellular respiration
C)  chemical synthesis
D)  photosynthesis
E)  carbon fixation

Question 16

You need to identify the major type of bacteria living on the shower curtain in your bathroom and find out what they use as a food source.What is the most efficient method for answering this question?

Accepted Answer

A)  enrichment culture
B)  direct sequencing
C)  Enrichment culture and direct sequencing are equally efficient methods.

Question 17

Which of the following describe all existing bacteria?

Accepted Answer

A)  pathogenic,omnipresent,morphologically diverse
B)  extremophiles,tiny,abundant
C)  small,harmful,fast-growing
D)  tiny,ubiquitous,metabolically diverse
E)  all of the above

Question 18

Which of the following statements best defines a psychrophile?

Accepted Answer

A)  A micro-organism capable of living in extremely cold environments.
B)  A micro-organism capable of living in environments with an extremely high salt concentration.
C)  A micro-organism that lives in an environment with moderate temperatures.
D)  A micro-organism capable of living in extremely hot environments.

Question 19

Biologists sometimes divide living organisms into two groups: autotrophs and heterotrophs.How do these two groups differ?

Accepted Answer

A)  They use different sources of energy.
B)  They use different electron acceptors.
C)  They use different sources of carbon.
D)  They differ in the way they generate ATP.

Question 20

Bacteria participate in the nitrogen cycle through which mechanism?

Accepted Answer

A)  nitrogen fixation
B)  nitrification
C)  denitrification
D)  decomposition
E)  all of the above

Exam 28: Bacteria and Archaea